Crystal Palace winger Wilfried Zaha faces around a month on the sidelines.
The Ivory Coast star, who has scored four goals this season, suffered a knee injury during last weekend's 1-1 draw with Newcastle.
The news is a major blow to Palace's survival hopes, not least because they have not won a league game without him since September 2016.
There were fears the Eagles could be without their talisman for the rest of the season, but manager Roy Hodgson said: "The good news is he's a very quick healer.
"He and the medical staff are working very hard to get him back on the field as soon as possible.
"He won't play at Everton on Saturday, and it may take a few weeks more than that. But we hope it won't be as long as all that.
"We'll take it on a match-by-match, week-by-week basis and get him back on the field as soon as we can.
"He's not out for the rest of the season. If he recovered in a week or two it would be a fantastic effort from his point of view.
"We may have to wait a month or so for him, but it's not certain. All the time the possibility and chance exist to get him back, we'll do that. He'll be pushing the medical people to come back as soon as possible."
Zaha himself confirmed the news that he will miss a chunk of Palace's relegation battle.
He wrote on Twitter: "After seeing a specialist over the last few days, I can sadly confirm that I will be on the sidelines for the next few weeks. Thank you to the fans for all your support and I hope to back playing again as soon as possible!"
Zaha is added to a lengthy injury list for Hodgson, who is also without Bakary Sako, Jeffrey Schlupp, Ruben Loftus-Cheek, Martin Kelly, Scott Dann, Jason Puncheon, Connor Wickham and Julian Speroni.
Deadline-day arrival Alexander Sorloth, the 6ft 4in striker signed from FC Midtjylland, could be pitched in for a debut against Everton at Goodison Park.